Induction-coil.



(No Model.)

Patented July 24, I900. B. A. FESSENDEN.

INDUCTION COIL.

(Application filed Deal 1, 1899.)

3 Sheets-Sheet 1 FIG].

Wrmsssss:

'P'atented July 24, 1900 3 Sheets-Sheet 2.

II. A. FESSEIIDEN.

INDUCTION COIL. A lication filed Dec. 1. 1899.) (No Model.)

lllllllIIIIIIIIIIIIIIIIIII NUE INVENTOR,

WITN ESSES:

. Patented July 24, I900. R. A. FESSENDEN.

INDUCTION, COIL.

(Application fll'ei'nqc. 1, 1899.)

3 Sheets-Sheet 3,

(No Iodel.)

m: NORRIS FEYENS co. PHOTOLITHO" wAsummzw. u L

'rrni) STATES PATENT OFFICE.

REGINALD A. FESSENDEN, OF ALLEGHENY, PENNSYLVANIA.

INDUCTION-COIL.

SPECIFICATION forming part of Letters Patent No. 654,390, dated July 24,1900. Application filed December 1, 1899. Serial No. 788,847. (Nomodel.)

To all whom it may concern: I

Be it known that I, REGINALD A.- FEssEN- DEN, a citizen of the UnitedStates, residing at Allegheny, in the county of Allegheny and State ofPennsylvania, have invented or discovered certain new and usefulImprovements in Induction-Coils, of which improvements the following isa specification.

The invention described herein relates to certain improvements-in theconstruction of induction-coils; and the invention has for one object aconstruction whereby the ends of the core may be brought into closeproximity to each other, thus rendering it possible to reduce theprimary winding withoutany reduction in the efficiency of the coil.

It is a further object of the inventionto provide for the adjustmentofltheair-gap between the ends ofthe core.

It is also an object of the invention to so locate the primary andsecondary coils that the latter will not inclose or surround the primarycoil, thereby permitting a free radiation of heat from the latter.

The invention is hereinafter more fully described and claimed.

In the accompanying drawings, forming a part of this specification,Figure 1 is a View in elevation of my improved coil shown connected incircuit for an X-ray apparatus. Fig.

2 is a sectional view of the coil, and Fig. 3 is a similar View of amodified construction.

In the practice of my invention the core 1 is formed by wrapping ironwire around a suitable former which maybe of suitable shape or contour.The former, with the wire thereon, is then boiled in'paraffin orothersuitable cementing material, whereby the strands of wire may becemented into a solid mass. soon as the cementing material has hardenedthe annulus (which is not necessarily circular, but may be oblong,square, or of any desired contour) is divided transverselyin one, two,or more places, as desired, and the divided annulus or the sections ofthe annulus are removed from the former. A sufficient number of windingsor turns of insulated wire are made around the arms or sections of thedivided annulus or core, the windings being connected in series orparallel and forming the primary coil 2. The primary coil or coils y donot extend along the entire length of the arms or sections of the core.

The secondary coils 3 are formed, as is customary, by winding fineinsulated wire on a suitable spool 4, formed of insulating material, andinclosing the coils in a case or shell 5, of insulating material. Whilethe secondary coils may be arranged at any desired point or points onthe oore, it is preferred that the ends of the core arms or sections beforced into central openings through the spools and shell of thesecondary coils. The ends of core arms or sections within the secondarycoils are held the proper distance apart by any suitable means-as, forexample, by a block 6,

. which is preferably made of thin disks of in sulating material, sothat by insertion or :re-

moval of one or more of these disks the distance between the ends ofthe'core arms or sections may be regulated.

While I have shown the core as divided at one or two points, it will beunderstood by those skilled in the art that it may bedivided into one ortwo sections, if desired, and one or two primary and secondary coils maybe used. here two primary or two secondary coils are used,.they areconnected in series, as shown at 7.

In order to prevent arcing between the primary and secondary coils, itis preferred to ground such coils on the core, as shown at 8 and 9.

It is characteristic of my improvement that by arranging the ends of thecore in compara= tively-close proximity to each other there is lessresistance in the magnetic circuit, and hence fewer windings arerequired'for the primary circuit for a given efficiency of theinduction-coil. By constructing the core in theform of adivided orsectional annulus the adjacent ends of the core may be moved toward andfrom each other to obtain the highest efficiency.

It will be observed that the primary coils are outside of the secondarycoils, permitting free ventilation, and thereby avoiding liability ofexcessive heating of the primary coil.

My improved induction-coil is especially applicable for use in X-rayapparatus, the bulb 9 of such apparatus being connected in series withthe secondary coils 3 and'the ter minals of the primary coils beingconnected, as is customary, With an electric generator and aninterrupter.

The term annulus as applied herein to the core is not limited to acircular or ringlike contour, but includes any shape or contour wherebythe ends of the divided or core sections may be brought into proximityto each other.

I claim herein as my invention- 1. An induction-coil having incombination a divided annular core, and primary and sec ondary coilssurrounding the core and so arranged that at least a part of each coilsurrounds the oore on both sides of the gap between the ends of thecore, substantially as set forth.

2. An induction-coil having in combination a divided annular core, aprimary coil and a secondary coil, said coils surrounding the core indifferent planes at right angles to the axis of the core and so arrangedthat at least a part of each coil surrounds the core on both sides ofthe gap between the ends of the core, substantially as set forth.

3. An induction-coil, havingin combination a divided annular core,primary coils surrounding core on opposite sides of the gap between theends of the core and secondary coils arranged intermediate of theprimary coils, substantially as set forth.

a. An induction-coil havingin combination a sectional annular core,primary coils surrounding the core intermediate of the gaps at the endsof the sections and secondary coils inclosing the ends of thecoresections, substantially as set forth.

In testimony whereof I have hereunto set my hand.

REGINALD A. FESSENDEN.

Witnesses:

DARWIN S. WoLcoTT, F. E. Giu'rnnn.

